Bioinspired Fluorine Labeling for 19F NMR-Based Plasma Amine Profiling.

Metabolite profiling serves as a powerful tool that advances our understanding of biological systems, disease mechanisms, and environmental interactions. In this study, we present an approach employing 19F-nuclear magnetic resonance (19F NMR) spectroscopy for plasma amine profiling. This method utilizes a highly efficient and reliable fluorine-labeling reagent, 3,5-difluorosalicylaldehyde, which effectively emulates pyridoxal phosphate, facilitating the formation of Schiff base compounds with primary amines. The fluorine labeling allows for distinct resolution of 19F NMR signals from amine mixtures, leading to precise identification and quantification of amine metabolites in human plasma. This advancement offers valuable tools for furthering metabolomics research.

Determining the Enantiomeric Excess and Absolute Configuration of In Situ Fluorine-Labeled Amines and Alcohols by 19F NMR Spectroscopy.

The determination of the enantiomeric excess and absolute configuration of chiral compounds is indispensable in synthetic, pharmaceutical, and biological chemistry. In this article, we describe an efficient 19F nuclear magnetic resonance (NMR)-based analytical protocol for determining the enantiomeric excess and absolute configuration of in situ fluorine-labeled amines and alcohols. 2-Fluorobenzoylation was used to convert analytes to fluorinated amides or esters. The resulting F-labeled analytes were mixed with a cationic cobalt(III) complex, [Co]BArF, resulting in clean baseline peak separations of analyte enantiomers in 19F{1H} NMR spectra. The measured ΔδRS signs were unambiguously used to correlate the absolute configurations of amines, amino alcohols, and alcohols. Moreover, the structure-dependent 19F{1H} NMR signals enabled absolute configuration determination by analyzing the relative chemical shifts of enantiopure analyte samples with [Co]BArF and ent-[Co]BArF.